title: Laccase-catalyzed phenol oxidation. Rapid assignment of ring-proton deficient polycyclic benzofuran regioisomers by experimental 1H-13C long-range coupling constants and DFT-predicted product formation.
abstract: Laccase-catalyzed oxidation of substituted catechols followed by reaction with 4-hydroxy-pyrone/-benzopyrone afforded substituted benzofuran regioisomers whose structures with only two aromatic protons in total prevent a rapid structural assignment. Based on the evaluation of (1)H-(13)C long-range coupling constants a rule of thumb could be deduced for an easy and unambiguous differentiation between the possible regioisomers formed. DFT frontier orbital calculations of the reactants offer an interesting tool to explain the regioselectivity of the key reaction.
authors.affiliation: Bioorganische Chemie, Institut für Chemie, Universität Hohenheim, Garbenstrasse 30, D-70599, Stuttgart, Germany.
authors.forename: Heiko
authors.initials: H
authors.lastname: Leutbecher
authors.forename: Gerhard
authors.initials: G
authors.lastname: Greiner
authors.forename: Robert
authors.initials: R
authors.lastname: Amann
authors.forename: Andreas
authors.initials: A
authors.lastname: Stolz
authors.forename: Uwe
authors.initials: U
authors.lastname: Beifuss
authors.forename: Jürgen
authors.initials: J
authors.lastname: Conrad
mesh_terms: D001572:Benzofurans / Q000737:chemistry*; D055162:Biocatalysis; D005583:Fourier Analysis; D042845:Laccase / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D010084:Oxidation-Reduction; D010636:Phenols / Q000737:chemistry / Q000378:metabolism*; D011522:Protons; D013237:Stereoisomerism; D013997:Time Factors; D055454:Trametes / Q000201:enzymology
chemical_list: D001572:Benzofurans; D010636:Phenols; D011522:Protons; D042845:Laccase; C105430:benzofuran